This invention relates to the growth of cell cultures and the harvesting thereof.
There are many biochemical and chemical analyses for which it is necessary to have a source of live cells. The culture of such live cells, is however, time consuming and has traditionally been carried out by hand, making it extremely labour intensive. The traditional approach has been to attempt to grow the necessary live cells on a substrate in a source of food for the cells, which is normally a liquid solution of various chemicals. The most common approach has been to grow the cells on the interior surface of a flask which can contain the necessary solution. However, the harvesting of the cell culture from the inner surface of the flask is time consuming and awkward because of the need to gain access through what is generally a narrow flask opening and also and also in view of the need to remove the cells from the surface in such a way that minimal damage occurs to them. In practice this has normally therefore required the expertise of a skilled technician. Furthermore, it has resulted in an operation employing some form of scraping implement, which can lead to repetitive strain injuries for the technician. Also, various other stages in biochemical and chemical analyses have been automated, the need for increased volumes of live cell culture has increased. Accordingly, there is a desire to automate the process of cell cultures, and the harvesting of live cell cultures. However, in view of the awkward nature of the scraping of such cell cultures and the need for the performance of complex precision manoeuvres in order to harvest the cell cultures, automation of harvesting has been particularly difficult to achieve.
The present invention seeks to provide an apparatus and method for improving the harvesting of live cell cultures either manually or automatically.
According to the present invention there is provided a scraper for scraping live cells from a substrate, the scraper comprising:
a core formed from magnetizable material; and
an elastomeric housing surrounding at least a portion of the magnetic core and defining at least one scraping blade.
The housing may totally encase the magnetic core. The scraper may have a hole formed in its centre. The housing may define plural scraping blades and may have a symmetrical cross-section.
According to the present invention there is also provided a system for scraping live cells from a substrate, the system comprising:
a scraper of the type defined above;
an magnetic or electromagnetic holder for holding the scraper when not in use; and
a magnetic force generator for generating, in use, a magnetic force that can be applied to the scraper in use to generate relative movement between the scraper and the substrate.
The holder may comprise a holding rod with a soft magnetic core and an electromagnet coil associated therewith. It may be shaped so that it can pass, together with the scraper, through the neck of a flask, the inner surface of which defines the substrate.
The magnetic force generator may be an electromagnet and may have means associated therewith for controlling the force applied to the scraper. This force controlling means may include means for controlling the separation between the scraper and the magnetic force generator in use. The magnetic force generator may also comprise means for generating movement between the substrate and the scraper.
The provision of the magnetic scraper according to the invention enables simple and effective scraping to be performed without the need for performance of a skilled operation by a human operator. It also provides a method of harvesting live cells which can increase the efficiency of harvesting and allow total automation of the harvesting process.